Water quality deterioration at a karst spring (Gallusquelle, Germany) due to combined sewer overflow: evidence of bacterial and micro-pollutant contamination

• Published in: Environmental earth sciences 2009-04, Vol.57 (4), p.797-808
• Main Authors: Heinz, B, Birk, S, Liedl, R, Geyer, T, Straub, K. L, Andresen, J, Bester, K, Kappler, A
• Format: Article
• Language: English
• Subjects: Aquifers; Bacteria; Biodegradation; Combined sewer overflows; Combined wastewater; Contamination; Drinking water; E coli; Earth and Environmental Science; Earth Sciences; Earth, ocean, space; Engineering and environment geology. Geothermics; Escherichia coli; Exact sciences and technology; Geochemistry; Geology; Hydrogeology; Hydrology. Hydrogeology; Karst; Micropollutants; Mineralogy; Organic carbon; Organophosphates; Original Article; Overflow; Pollutants; Pollution, environment geology; Public waters; Sewage disposal; Silicates; Spring water; Stormwater; Stormwater management; Studies; Turbidity; Water geochemistry; Water management; Water quality; Water resources; Water supply
• ISSN: 0943-0105; 1866-6280; 1432-0495; 1866-6299
• DOI: 10.1007/s00254-008-1359-0

The concurrent use of karst aquifers as drinking water resources and receptors of combined sewer overflow lacking appropriate pre-treatment may cause conflicts between drinking water supply and storm water management. A storm water tank (SWT) for combined wastewater is identified as the source of sporadic contamination of a karst spring (Gallusquelle, “Schwäbische Alb”, SW Germany) used for public water supply. Spring water quality was examined by routine and event sampling and by evaluating physicochemical and microbiological parameters. The total number of microbial colonies growing at 20°C and the number of Escherichia coli colonies rose to values up to four orders of magnitude higher than background, 2-5 days after overflow of the SWT. High concentrations of chloride, sodium, and total organic carbon (TOC) and high values of turbidity coincide with this increase. However, high bacterial contamination is also observed while turbidity and TOC are low. Several wastewater-related organic micro-pollutants such as chlorinated and non-chlorinated organophosphates were detected in the SWT and, depending on their K ow values and their biodegradability, in lower concentrations at the spring.